The Duvaucel's gecko - which can grow more than 12ins (30cm) long - was found at the Maungatautari wildlife reserve in North Island's northern Waikato region.

Chris Smuts-Kennedy, a Maungatautari ecologist, said the death of the gecko was a cruel irony but that this meant the reserve may be home to more members of the species.

"The most likely scenario is that it represents a surviving population, and this is a species which has been thought to be extinct on the mainland for probably close to a century,"

The only confirmed populations of the gecko, which can live up to 50 years, are on predator-free offshore islands. The reptile is vulnerable to attacks by pests, especially rats.

The last time the gecko was seen on the mainland was thought to have been in the 1920s in the Thames area, southeast of Auckland, Smuts-Kennedy said.

Maungatautari staff and volunteers hope to survey the mountain in search of more of the geckos.

Maungatautari is a forested volcano, where introduced pests have been eradicated and a 29-mile (47km) predator-proof fence built to allow the reintroduction of rare native species, including the kiwi.

New Zealand's native birds, reptiles and insects evolved in a predator-free environment before humans arrived in the last 800 or so years and many have been wiped out by introduced species, especially rats, stoats and possums.